[e2e] node addresses vs. interface addresses

[Joe Touch]

J. Noel Chiappa wrote:
>     > From: Joe Touch <touch at ISI.EDU>
> 
>     >> it's putting the entire cost of multi-homing .. into the routing,
>     >> where the cost is paid by everyone (effectively - long arcane routing
>     >> point elided) across the network
> 
>     > Except again that this can be hidden from the rest of the network using
>     > tunnels. A host can have a single endpoint address - on an "internal"
>     > virtual interface, used through a set of tunnels, each using outer
>     > addresses based on one of multiple real interfaces.
> 
> I must be missing something here. (I looked at the ICNP paper, but it had
> nothing about tunnels, and the tunneling I-D didn't have much to say about
> multi-homed hosts.)
> 
> Although you didn't provide full details of how it works,

Hmm. Actually, there are config files.

> when I try to think
> of schemes using tunnels to do multi-homing, either i) the host on the other
> end emits wrapped packets (i.e. with the outermost destination IP address
> being one of the "multiple real interfaces"), in which case this isn't a
> general solution, since not all correspondent hosts will be prepared to do
> that,

That's what we do. Yes, not all hosts are prepared to do that - but they 
should be, and that's a lot easier than creating yet another new 
protocol that ends up being equivalent.

Joe